Method and apparatus for the productiok op extruded tubirg



DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request at the applicant or owner in accordance with the Notice ot Dec. 16, 1989. 809 0.6. 081'. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number or pages of specification, including claims and sheets or drawings cantnijied in the application as originally tiled. The files at these applications are available to the public for inspection and reproduction may be purchased tor 80 cents a sheet.

Defensive Publication applications have not been examined as to the merits oi alleged invention. The Patent Otlice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED APRIL 1-1, 1970 6 Int. Cl. 1529c 17/07; B29d 23/ 04 US. Cl. 26490 2 Sheets Drawing. 5 Pages Specification A method and apparatus are disclosed for the production of extruded tubing made of polymeric materials. The process consists of the sequential steps of extruding the polymeric material first through a water-cooled vacuum sizing die having a smooth central bore (1) with a vacuum zone at either end, and then a contraction die having a smooth passageway (23) therethrough a decreasing size from the entry point to the exit point. The contraction die is mounted adjacent to the vacuum die (FIG. 3). v

The preferred polymeric material to be used according to the process is 4-methyl pentene-l. Because of the high melting point of 4-methyl pentene-l, tubing thus produced has a smooth surface finish, can be easily sterilized, and. is suitable for laboratory, hospital and dairy equipment.

A hot extruded parison at a temperature in excess of the melting point of the polymeric material is passed into the vacuum die, suction is applied through the vacuum zone thereby causing the tubing to conform to the smooth surface ofthe bore. The heated tubing is then passed into the contraction die where it cools and contracts. Tubing having a smooth surface finish results,

on T $13.00?

April 14, T873,001

I D TUBING Filed Juno 2, 1969 a Sheets-Sheet 1 aw-saa SF:

on T 13.00?

April 1970 A. P. BENNETT ETAL T873,001

METHOD AND APPARATUS FOR THE PRODUCTION OF EXTHUDED TUBING Filed June 2. 1969 3 Sheets-Sheet 8 

